Development of an auto-focus system based on the moiré method

Ju Yi Lee; Yung Hsing Wang; Lyu Jhen Lai; Yu Ju Lin; Yu Hsiu Chang

doi:10.1016/j.measurement.2011.08.026

Development of an auto-focus system based on the moiré method

Ju Yi Lee, Yung Hsing Wang, Lyu Jhen Lai, Yu Ju Lin, Yu Hsiu Chang

Department of Mechanical Engineering

Research output: Contribution to journal › Review article › peer-review

18 Scopus citations

Abstract

An auto-focus system based on the moiré effect and a feedback control method is presented. First, a collimated laser beam passes through a focusing lens then falls incident on the surface of the sample. The deviation of the angle of the light reflected back is proportional to the defocus distance from the sample. The reflected light then passes through two spiral gratings, producing three types of moiré pattern which can be observed and recorded by a linear CCD. The defocus distance can be derived from the spiral angle in the moiré pattern. The results show that auto-focusing can be achieved by the moiré method for glass and mirror samples in a cycle time of less than 0.1 s.

Original language	English
Pages (from-to)	1793-1800
Number of pages	8
Journal	Measurement: Journal of the International Measurement Confederation
Volume	44
Issue number	10
DOIs	https://doi.org/10.1016/j.measurement.2011.08.026
State	Published - Dec 2011

Keywords

Auto-focus
Moiré
Spiral grating

Access to Document

10.1016/j.measurement.2011.08.026

Cite this

@article{a97b66564a5c47c99a2061baeb706e0a,

title = "Development of an auto-focus system based on the moir{\'e} method",

abstract = "An auto-focus system based on the moir{\'e} effect and a feedback control method is presented. First, a collimated laser beam passes through a focusing lens then falls incident on the surface of the sample. The deviation of the angle of the light reflected back is proportional to the defocus distance from the sample. The reflected light then passes through two spiral gratings, producing three types of moir{\'e} pattern which can be observed and recorded by a linear CCD. The defocus distance can be derived from the spiral angle in the moir{\'e} pattern. The results show that auto-focusing can be achieved by the moir{\'e} method for glass and mirror samples in a cycle time of less than 0.1 s.",

keywords = "Auto-focus, Moir{\'e}, Spiral grating",

author = "Lee, {Ju Yi} and Wang, {Yung Hsing} and Lai, {Lyu Jhen} and Lin, {Yu Ju} and Chang, {Yu Hsiu}",

note = "Funding Information: This study was supported by the Industrial Technology Research Institute, Taiwan, under Contract Number B200-99LE2.",

year = "2011",

month = dec,

doi = "10.1016/j.measurement.2011.08.026",

language = "???core.languages.en_GB???",

volume = "44",

pages = "1793--1800",

journal = "Measurement: Journal of the International Measurement Confederation",

issn = "0263-2241",

number = "10",

}

TY - JOUR

T1 - Development of an auto-focus system based on the moiré method

AU - Lee, Ju Yi

AU - Wang, Yung Hsing

AU - Lai, Lyu Jhen

AU - Lin, Yu Ju

AU - Chang, Yu Hsiu

N1 - Funding Information: This study was supported by the Industrial Technology Research Institute, Taiwan, under Contract Number B200-99LE2.

PY - 2011/12

Y1 - 2011/12

N2 - An auto-focus system based on the moiré effect and a feedback control method is presented. First, a collimated laser beam passes through a focusing lens then falls incident on the surface of the sample. The deviation of the angle of the light reflected back is proportional to the defocus distance from the sample. The reflected light then passes through two spiral gratings, producing three types of moiré pattern which can be observed and recorded by a linear CCD. The defocus distance can be derived from the spiral angle in the moiré pattern. The results show that auto-focusing can be achieved by the moiré method for glass and mirror samples in a cycle time of less than 0.1 s.

AB - An auto-focus system based on the moiré effect and a feedback control method is presented. First, a collimated laser beam passes through a focusing lens then falls incident on the surface of the sample. The deviation of the angle of the light reflected back is proportional to the defocus distance from the sample. The reflected light then passes through two spiral gratings, producing three types of moiré pattern which can be observed and recorded by a linear CCD. The defocus distance can be derived from the spiral angle in the moiré pattern. The results show that auto-focusing can be achieved by the moiré method for glass and mirror samples in a cycle time of less than 0.1 s.

KW - Auto-focus

KW - Moiré

KW - Spiral grating

UR - http://www.scopus.com/inward/record.url?scp=80054983519&partnerID=8YFLogxK

U2 - 10.1016/j.measurement.2011.08.026

DO - 10.1016/j.measurement.2011.08.026

M3 - 回顧評介論文

AN - SCOPUS:80054983519

SN - 0263-2241

VL - 44

SP - 1793

EP - 1800

JO - Measurement: Journal of the International Measurement Confederation

JF - Measurement: Journal of the International Measurement Confederation

IS - 10

ER -

Development of an auto-focus system based on the moiré method

Abstract

Keywords

Access to Document

Fingerprint

Cite this